Venetian blind



Dec. 26, 1950 J. L. HUNTER ETAL 2,535,926

VENETIAN BLIND Filed March 1, 1948 IN VEN TOR5 moms Amer/N BY g/oszm/l.f/u/vrm Patented Dec. 26, 1950 Jsoseplr L.. Hunter and Thomas Martin,Riverside,

Calif... assignors; by mesne assignments, to Hunter. Douglas:Corporation, Riverside, Galifl, a corporation. t Delaware.

Application March: 1, 1948; SerialNo. 12 447 Our invention relates toVenetian blinds and has particular reference to. a noveh type; of Veneblind ladder employing slightly stifi cross bars. so: that. accidentalangular misalignment of one slat: with respect to another may beavoided.

Venetian blinds: ordinarily employ a plurality of: supporting ladders,between; which are. spaced slats to form the. blind element of theVenetian blind. These. ladders: include two vertical. tapes and aplurality of cross bars: secured between the tapes, and the slats are.supported upon these cross barsorhungs?" of the ladder- The amount oflight passing through a. Venetian blind is controlled by adjusting theangular disposition oi the slats, which is. accomplished by lifting onevertical. tape of the. ladder with respect to the other. The cross. barsof the. ladder are thus inclined, causing the slats. to become similarlyinclined.

It frequently happens, however, that; persons or articles touch aVenetian blind suificiently hard so that the angular disposition of oneor more of the slats is changed, thus giving an uneven appearance to theblind, permitting localized diflerences in light transmission, eithermore or less light. transmission. The ability of individual slats: tohave their orientation thus changed is. due to the fact that the crossbars of the ladder are generally formed of an extremely flaccid fabricmaterial which yields to conform to a particular disturbance of the;angular position of the slat.

Our invention providesa Venetian blind ladder wherein. accidentaldisturbances or changes of the angular position of some of the slats isprevented by providing a semi-rigid type of cross bar for Venetian blindladders, which cross bar will restore a Venetian blindslat to itsselected angular position. Ladders built in accordance with ourinvention therefore include a pair of flaccid vertical tapes havingcross bars of stiffened material. It is essential that the verticaltapes be flaccid inasmuch as they must adequately bunch or loop when theVenetian blind I1'Claims- (CL, 160 -178 that; extends approximatelytwo-thirds of the distance across the. slat. Inasmuch as. Venetian blindslats are made from either very flexible metal, only .002 or .003 of aninch thick orthin wood, the eiiect of the notch is to weaken the slatrequiring support by the cross bar on either side of the notch. Thissupport has heretofore been imperfectly rendered. by a fabric type ofcross bars. but the semi-rigid cross bar as provided by our inventionpositively supports the slat on either side of the notch, thuspreventing a warping of one part of the slat with respect. to the.other.

It is therefore a principal object of our invention to provide aVenetian blind wherein a slat will be restored to an angular position asdetermined by the angular position of the cross bars when the slat isaccidentally displaced to another angular position.

Another object of Our invention is to provide a Venetian blind ladderwherein the cross: bars are of greater rigidity than the vertical tapes.

A further object of our invention is to provide a plastic type ofVenetian blind ladder wherein the plastic of the cross bar is of greaterrigidity than the plastic of the vertical tapes. A further ob ect of ourinvention is to provide a Venetian blind ladder wherein a cross bar isprovided that adequately supports a slat or the removable type.

Other objects and advantages of our invention will be apparent from astudy of the following specifications, read in connection with theaccompanying drawing, wherein l is a perspective fragmentary view of aVenetian blind ladder embodying our invention and illustrated as usedwith a removable type, of Venetian blind slat:

Fig. 2 is an enlarged perspective view, from the under side. of one ofthe cross bars of Fig. 1; Fig. 3 is a perspective view of a fragment ofa preferred form of vertical tape incorporating our invention; and

Fig. 4 is an elevation view of a fragmentary portion of a Venetian blindladder embodying our invention.

Referring to Fig. 1, a Venetian blind it may include a plurality ofgenerally horizontal slats I I supported by a plurality of ladders !2that are provided particularly in accordance with our invention. Onlyone such ladder I 2 is illustrated but it will be obvious that a pair ofladders is generally emp oyed between which the slats I! extend. Alifting cord l3 of any suitable material'may be provided that passesthrough the slats II and through apertures in the cross bars or rungs ofthe ladder I2.

While our invention is applicable to any type of Venetian blind, we willdescribe it as used with a Venetian blind employing removable slats.Accordingly, ,the slats ll may be provided with transverse notches l4that extend at least half way across the width of the slat andpreferably approximately two-thirds of the distance. These slats may beremoved from the ladder I2 by rotating them manually to a verticalposition and then sliding them longitudinally from between the ladders.It Will be noted, however, that the notch I 4 greatly weakens the slatsII and if the slat is not supported on both sides of the notch one sidewill tend to droop or twist with respect to the other part, thus givingrise to an unsightly appearance.

The ladder I2 may include a pair of vertical tapes I5 having cross barsor webs I5 extending between them, which webs may be stiffened inaccordance with our invention. These cross bars I6 may have a stiffnessequivalent to thick parchment paper, or corresponding approximately tothat of a playing card, so that the weight of a canted slat may beeasily borne by the cross bar without appreciable bendng. This is incontrast to the physical characteristics required for the vertical tapesI5, which tapes must be extremely flaccid and pliable so that they maybe properly folded into loops or gathers at the top of the Venetianblind when the slats are raised to be in surface to surface contact witheach other. Another important advantage of the semi-rigid cross bars isthe fact that they remain flat in the transverse direction at all times,and therefore have no tendency to fold up and enter the notch I4 whenthe slat is canted; which occurs frequently when notched removable slatsare used with convent onal flaccid cross bars. Each full width cross barUS may be provided with a central aperture 2! through which the liftingcord I3 may pass.

While various techniques may be employed in practicing our invention toach eve greater rigidity of the cross bar I6 with respect to thevertical tapes, at present we prefer to achieve this relative flexibiltyby employing materials formed of organic plastic, utilizing a stiffermaterial for the cross webs it than for the vertical tapes I5.

We have found that certain of the vinyl res ns have the requiredflexibilities for these two different applications and by employingresins of the same basic type they may be easily heat welded orotherwise bonded together. For example, we have found that the vert caltapes I5 may be satisfactorily formed of vinyl chloride-acetatecopolymer that has been plasticized with a high boiling pointplasticizer such as tricresyl phosphate so that it is flaccid or pliablein the same sense that woven fabrics are pliable. Thus this plasticizedmaterial may be formed into sheets or strips of the desired size for thevertical tapes 15. The cross bars I6, however, may be formed ofvinylidene copolymer or vinyl chloride or vinyl chloride-acetatecopolymer in its so-called natural state or unplasticized state, or inthe state wherein very little plasticizer is employed to soften thematerial.

Considerable variation in the properties is obtainable by varying thedegree of polymerization or the relation of vinyl chloride to vinylacetate, or the amount of plasticizer. Also the properties may be variedby pigmenting or compounding. Hence the rigidity or flexibility of thedesired cross web may be suitably controlled in the fabricating process.The type of plastic cross web we presently prefer may have aparchment-like stiffness feel and may be on the order of .012 to .015 ofan inch thick. The material is readily bent by the fingers to anydesired shape but upon standng will assume its original shape, forexample, flat sheets. The material is generally rigid as to small forcesand, in fact, is commercially referred to as rigid vinyl resin sheetswhen supplied in sheet form.

We have further found that the assembly of rigid vinyl resin cross barsto flaccid vinyl resin vertical tapes may be facilitated by the use ofprojecting cross bar stubs on the vertical tapes. Additionally, theprovision of such stubs gives rise to a great flexibility in the moreflaccid material, thus permitting the cross bars I6 to remainsubstantially unflexed, and also reducing flexing of the vertical tapes.

Referring to Fig. 3, it wil be noted that the vertical tape I5 may beprovided with a series of cross bar stubs I! in the form of projectingridges. By reference to Fig. 4, it will be noted that each stub I! isjoined to the vertical tape I5 by a filleted joint as at I'Ia. Thesemi-rigid cross bar I5 may be secured between a pair of the verticaltapes I5 by bonding to the tips of oppositely disposed stubs IT.

The stubs ll may be formed on the vertical tapes I5 in any desiredmanner and we have found that they may be suitably formed of the samecomposition as the vertical tapes I5 as extrusions and then cut inlengths equivalent to the width of the vertical tapes I5 and heat bondedsolvent adhered, glued or otherwse secured to the vertical tapes.Additional'y, the vertical tapes may be molded in a mold provided withtransverse recesses of a size and shape to form the filleted projectingstubs I'I. Also if desired the vertical tapes I5 may be reinforced withthreads, pliable fabric or other material to prevent elongation underload.

The attachment of the rigid vinyl chlorideacetate cross bar I6 to thestub Il may be obtained by cementing or by heat bonding. adhesion of thecross bars to the stubs, the tips of the cross bar and the stubs may befirst softened by a suitable solvent, preferably solvents of the slowacting type so as not to craze or locally weaken the sheet; Softeningsolutions are well known in the industry and by way of example mayinclude methyl acetate, ethyl acetate, methyl ethyl ketone, methylenedichloride and cyclohexanone. ably softened they may be overlapped andpressed together and upon evaporation of the thinner solvent the sheetswill be strongl adhered to each other. Adhesives may also be used, themost successful of which are based upon the synthetic rubbers and alsoupon latex solutions.

Heat bonding may be used either with or without the use of a preliminarysoftener. Heat bonding in most cases may take place below 200 F. buthigher temperatures may be utilized for stronger bonds.

It should be noted that where our cross bars are employed with removableslats the cross bar is preferably of the same width as the width of thevertical tapes so as to give adequate support to the slat on either sideof the notch I4. However, standard patterns of staggered arrays of crossbars may be utilized with standard types of slats inasmuch as onlyfractional width cross For After the two joining materials are suitbarsare necessary. Full width cross bars may be slightly narrower thanvertical tapes for the sake of appearance.

In operation, one vertical tape [5 may be lifted by the usual tiltingmechanism (not shown) with respect to the other, thus disposing thecross bars 16 at an angle. The slats l I resting on the cross bars IEwill assume a corresponding angle. The flexing of the cross bars as awhole may take place in the stub portion I1, thus relieving thesemi-rigid cross bar I6 of stresses. Hence, each stub portion forms aflexible articulated joint connecting one end of the attached cross barto the adjacent vertical tape. If the slats should be accidentallydisturbed to a new position, the cross bar I6 will tend to maintain itsstraight position, thus causing the slat to return to the positiondesignated by the tilt of the cross bar. This is in contrast to flaccidcross bars wherein the slat will remain at any angle to which it isdisturbed.

While at present We prefer to use vinyl resin materials for our improvedVenetian blind ladder, it will be obvious to those skilled in the artthat various other materials may be utilized; for example, standardfabric Venetian blind ladders could be employed wherein the fabric crossbar is stiffened by the application of a paint, plastic wax or othermaterial so that it will have suflicient rigidity to act in accordancewith our invention. Also various other plastics may be employedincluding, by way of example only, the cellulose acetate compounds,various of the modifled or chlorinated synthetic rubbers, polymers ofchloroprene, ethyl rubber, etc. Accordingly, the recitation of vinylresins is by way of example only and We include within the true spiritand scope of our invention all such materials as will give the resultdescribed. The primary requirement is that the cross bar shall havesufficient rigidity to have but little deflection when a slat isaccidentally distorted so that one edge bears along a medial portion ofthe cross bar. The use of the stubs as hinges permits the use of evenvery rigid material for cross bars and for example we may employ acryliccopolymer as a cross bar material.

For these and various other reasons, it will be obvious that thedisclosed embodiment is merely illustrative and is not limiting ordefinitive of our invention.

We claim: I

1. A Venetian blind ladder comprising flaccid vertical tapes andsemi-rigid cross bars connected to and extending between said tapes, atleast the major portion of said cross bars having substantially greaterrigidity than the vertical tapes.

2. A Venetian blind ladder as defined in claim 1 in which said majorportion of the cross bars has a rigidity sufficient to support aVenetian blind slat without sagging under the weight thereof.

3. A Venetian blind ladder as defined in claim 1 in which the verticaltapes and cross bars are of resinou material.

4. A Venetian blind ladder as defined in claim 1 in which the verticaltapes and cross bars are of a vinyl resin, and in which the verticaltapes contain suificiently more plasticizer than said major portion ofthe cross bars to make them substantially more flaccid.

till

5. A Venetian blind ladder as defined in claim 1 in which the verticaltapes are of plasticized vinyl chloride and said portion of the crossbars is of a vinyl acetate-chloride copolymer.

6. A Venetian blind ladder comprising flaccid vertical tapes andsemi-rigid cross bars connected to and supported between said tapes,each cross bar having the major portion thereof of substantially greaterrigidity than the vertical tapes and stubs extending from the verticaltapes of greater flexibility than said major portion of the cross barsand connecting the vertical tapes to said portion of the cross bars andforming articulated joints between the vertical tapes and said portionsof the cross bars.

7. A Venetian blind ladder as defined in claim 6 in which the hortsections at each end of the cross bars are of the same material as andintegral with the vertical tapes.

8. A Venetian blind ladder as defined in claim 6 in which the shortsections of greater flexibility at each end of the cross bars are of thesame material as and integral with the vertical tapes, and in which theportions of the cross bars of greater rigidity form a butt joint withsaid short sections.

9. A Venetian blind ladder as defined in claim 6 in which the verticaltapes are of resinous material and the short sections of greaterflexibility at each end of the cross bars are integral with the verticaltapes and of the same resinous material.

10. A removable-slat Venetian blind comprising flaccid vertical tapesand semi-rigid cross bars connected to and extending between said tapes,said cross bars having an aperture for receiving a lifting cord, slatsbetween said vertical tapes and supported by the respective cross bars,each of said slats having a notch extending inwardly from one side edgethereof with inner portions of the notches aligned with the respectiveapertures of the cross bars, and a lifting cord extendin through thealigned apertures and notches, the width of the notches in the slatsbeing sufliciently narrow that edges of the slats defining the sides ofthe notches rest upon the respective cross bars, at least the majorportion of said cross bars having substantially greater rigidity thanthe vertical tapes and a rigidity sufficient to support the respectiveoverlying slats without sagging under the weight thereof, whereby theedges of the slats defining the sides of the notches are maintained inalignment.

11. A removable-slat Venetian blind as defined in claim 10 in which thecross bars are of substantially the same width as the vertical tapes.

JOSEPH L. HUNTER. THOMAS MARTIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Num er Name Date ,05 ,379 Brent Aug. 25, 1936 2,23,010 Kahn July 5, 1938 ,202,752 Brenner May 28, 1940 90,634 Clark July21, 1942 2,405,579 Hunter Aug. 1 1946

